不同培养载体对小麦条锈菌夏孢子人工萌发的影响

Effects of culture substrates on artificial germination of Puccinia striiformis f. sp. tritici

为探索适合小麦条锈菌寄主体外萌发的载体,并建立基于不同研究目的的小麦条锈菌夏孢子人工萌发技术,采用超声波水雾培养法,以小麦条锈菌生理小种CYR32为供试材料,探讨了不同培养载体对小麦条锈菌夏孢子萌发特性的影响。在最适温度和湿度条件下,以4种不同材料为培养载体,小麦条锈菌夏孢子的萌发率、芽管生长率和外观显示情况有显著差异。在尼龙纱网上的夏孢子萌发速度和芽管伸长速度最快,12h内萌发率最高可达93.40%,芽管最长可达446.71μm;亲水滤膜上夏孢子的萌发率和芽管长仅次于纱网;亲水塑料膜和PVDF膜上夏孢子的萌发率均高于普通亲水载玻片,而芽管长度低于普通亲水载玻片。采用侧光照明时,在亲水滤膜和PVDF膜上极易清晰观测到夏孢子及其芽管内的黄色颗粒物。在亲水塑料膜上,还可观察到夏孢子萌发12h后,芽管尾部膨大形成类似附着胞的结构。结果显示,超声波水雾可使条锈菌夏孢子处于水分饱和的环境,而纱网纤维组成的小格具有很好的保水结露功能,能使夏孢子萌发快,萌发效率高,芽管生长快;另一方面,使用其他培养载体还可满足观测条锈菌夏孢子内黄色颗粒物向芽管内转移和芽管尾部形成类似附着胞结构的目的。

The optimum culture substrates were explored to build a technique for artificial germination of Puccinia striiformis f.sp.tritici for different purposes.Aeroponics system was performed to investigate the effects of five different culture substrates on germination of CY32 uredospores.By microscope,we found that there was significant difference in germination ratio and length of urediniospore germ tubes among the five culture substrates under the optimal temperature and humidity,including hydrophilic Gel Bond PAG film,polyvinylidene fluoride film（PVDF）,0.45μm millipore filter,200μm×150μm gauze and hydrophilic glass slide.200μm×150μm gauze was the best substrate,followed by the 0.45μm millipore filter.On the gauze,the germination ratio could reach 93.40% and germ tubes grew to 446.71μm in 12 hours.In comparison to glass slide,Gel Bond PAG film and PVDF film led to a marked increase in germination rate,as well as a decrease in length of germ tubes.When we used side light,yellow particulates in uredospores and germinated tubes were observed on PVDF and millipore filter.On hydrophilic Gel Bond PAG film,we observed the end of tubes formed similar appressorium 12 hours after germination.The experimental results showed that aeroponics system made a water saturated condition for uredospores and the cells of gauze could hold water,both of which led to a fast and high germination;on the other hand,we could observe movement of yellow particulates and formation of appressorium using other culture substrates.Our studies can help understand the germination mechanism and pathogenic mechanism of P.striiformis f.sp.tritici and other pathogen spores.